The objective of the project is to develop an integrated model of the Global Change cycle and to use it to calculate the evolution of the CO2 accumulation in the atmosphere during the next decades based on socio-economic scenarios. This coupled model will be based on tools and expertise of the three participating teams. The ocean carbon module will be based on the existing model at LPAP (University of Liège) which will be improved to include consideration of coastal biogeochemical cycles, a field of expertise of the Free University of Brussels. The role of the biosphere (including soil carbon) as a sink or source of carbon will be described using a future time-dependent version of the CARAIB model. Particular attention will be given to the validation of the calculated biospheric productivity and net ecosystem productivity . The seasonal and interannual CO2 concentration will be calculated using a 3-dimensional atmospheric transport model and compared to the signal measured at various stations. Satellite remote sensing will also provide a global validation method. For this purpose, the Center for Teledetection and Atmospheric Processes of VITO will provide its expertise in vegetation remote sensing to use the AVHRR/NOAA sensor data for validation and data assimilation in the model.At the end of this project, a global carbon cycle model will be available. Simulations predicting the level of atmospheric CO2 will be made for various socio-economic scenarios.